How are steel pipe column groups welded?

1. Conditions for welding operations
1. Operators
There are two types of welding operators, equipment operators and welding personnel. The former must undergo professional technical training and obtain relevant qualification certificates before performing steel pipe welding operations, while the latter must pass relevant technical inspections and obtain professional certificates before they can be employed. Safety protection equipment must be prepared during construction to ensure the safety of construction workers.
2.Work tools
After the personnel are ready, they need the help of material conditions. Including drawings, grinder, wire brush, lifting equipment, anti-blocking agent, flat shovel, weld gauge, etc.
2. There are steps for welding operations
1. Preliminary preparation
(1) Understand the drawing requirements and ensure the quality of tool parts.
(2) Repeatedly check whether the overall specifications of the assembled steel pipe joints or components meet the requirements of the drawings, and whether the welding materials and welding grooves meet the quality requirements of the drawings and process standards.
(3) Check whether the equipment, tools and power supply required for operation are complete.
(4) Pay attention to the environment in the welding area:
①Ambient temperature: The working environment temperature is -10 degrees < . When the temperature is lower than -10 degrees, welding is not suitable and a special plan to ensure welding quality must be formulated before construction can be carried out strictly according to the construction plan.

②Ambient humidity should be greater than 90%

2.Implementation process
(1) Use lifting equipment to lift the component onto the tool rack and keep the welding point in a flat welding position as much as possible. For locations with few welds, horizontal welding and vertical welding can be used to connect.
(2) Check for oil, rust, moisture and other debris within 20mm of the component welding area.
(3) Select welding materials and adjust welding parameters according to engineering welding process requirements.
(4) Before welding, preheat accordingly according to the material to be welded and the ambient temperature.
(5) Main structure welds with a thickness greater than 40m and made of Q235 material or above.
(6) When the welding environment temperature is lower than 0 degrees and not lower than -10 degrees, the base material in the welding area of the seam assembly should be heated to 20 degrees, which is greater than or equal to twice the welding temperature. The thickness of the steel plate shall not be less than 100mm. Welding can be carried out after the above; when the minimum preheating temperature of the base material is higher than 20 degrees, a higher preheating temperature should be used for preheating.
(7) When welding square and rectangular pipe sections to the diaphragm, the welding sequence must be strictly controlled. The arc transition section can be welded in a vertical upward welding position, with the start and end positions of the arc transition section extending a certain distance to both sides. When welding nodes, you can also weld nodes vertically and horizontally.
(8) Strictly abide by the welding process regulations of the specific project during the welding process, and control the temperature between passes to reduce welding stress and deformation. Measures such as "C" clips can be used in overall assembly welding to reduce welding distortion.
During the welding process, it is necessary to continuously observe the welding status and weld quality, and make timely adjustments when abnormalities occur. The thickness of each weld should not be greater than 5mm, and the width of each weld should not be greater than 15mm. When single-pass welding cannot meet the weld size requirements, multi-layer multi-pass welding is required, and the inter-layer temperature must be strictly controlled. The interlayer temperature should not be lower than the minimum preheating temperature or higher than 230C.
(9) After the parts are welded, use a flat shovel or sharpener to remove burrs, welding slag and poor welds on the surface of the steel parts. If there are any defects, they should be repaired. After the weld has completely cooled and reached non-destructive testing conditions, perform non-destructive testing on the full penetration weld. If defects exceeding the standard are detected, gouging or grinding machine can be used to remove the defects and repair welding.